Advantages (29)

a. Rapid initiation of HT

b. No overshoot of core temperature during induction

c. Variability of core temperature during maintenance

and rewarming phase is minimal.

d. Better hemodynamic stability in terms of blood pressure and heart rate than manual cooling (Fig. 45.11,

upper panel).

A B

C

Fig. 45.16. Tecotherm Neo—

servocontrolled. A: Cooling unit.

B: Coolant. C: Tecotherm Neo setup

for cooling.

Fig. 45.15. Impressions on the skin produced by ECG leads under

the wrap, which are the result of applying the CureWrap too tightly.

e. Equipment suitable to be secured in ambulance

and used during transport.

f. Easy downloading of all temperature data.

2. Tecotherm Neo (Fig. 45.16) (TECCOM

GmbH, Halle/Salle, Germany)

Equipment

a. Mains cable

b. Tecotherm Neo cooling unit

c. Cooling mattress

d. Mattress connecting hoses

e. Rectal temperature probe × 2

f. Lubricating jelly

g. Skin temperature probe × 1

h. Coolant fluid

i. Coolant fill-up set

j. Pillow of six-layered bubble wrap

Technique

a. Connect the mains cable to the power and switch

on.

b. Connect the fill-up set to the cooling unit (Fig.

45.16B).

c. Keep the fill-up set above the cooling unit so that

the coolant fills up the cooling unit.

d. Connect the mattress to the cooling unit with the

connecting hose (Fig. 45.16A, C).

e. Connect the rectal temperature probe and the

skin temperature probe to the cooling unit (Fig.

45.16C).

f. Set the Tecotherm Neo to programmable servocontrolled mode (this completes the induction and

338 Section IX ■ Miscellaneous Procedures

maintains the temperature at the target of 33.5°C

for 72 hours, followed by servocontrolled rewarming

to 37°C over 7 hours).

g. Undress the infant down to small diaper.

h. Secure two rectal temperature probes to 6 cm (Fig.

45.2), and tape to the side of the thigh as previously

described in E.

i. Secure the skin temperature probe on the forehead.

j. Place the infant supine on the mattress and encircle

the baby with the mattress, in a closed unheated

incubator or an open crib/bed (Figs. 45.16 and

45.17)

k. Secure the mattress at the front of the infant with

the supplied ties (Figs. 45.16C and 45.17).

l. Place the pillow between the head and the mattress (30) (Fig. 45.17). Alarms are activated if there

is no power, low fluid, no flow of fluid, rectal temperature is out of range by 0.5°C, and for system

failure.

 

2. Set the coolant temperature in the cooling unit to

20°C.

3. Place the mattress inside an incubator with power

turned off.

4. Undress the infant down to small diaper to maximize

skin contact with mattress for optimal heat exchange.

5. Secure a rectal temperature probe to 6 cm (see Fig.

45.2E).

6. Place the infant on the mattress inside the incubator.

7. When the rectal temperature reaches 35°C, increase

the set temperature in the cooling machine to 25°C.

8. To maintain the rectal temperature between 33°C and

34°C, set temperature in the cooling machine to

between 25°C and 30°C. This will vary with the body

weight and heat production of the infant.

9. To rewarm the infant at 0.5°C/h, increase the set fluid

temperature in the cooling machine by approximately

0.3°C/30 minutes. The core temperature will increase

with increases in the mattress temperature. This is very

difficult to get “right” and requires experience.

10.When core temperature of (36.5°C) has been reached, set

the incubator temperature to maintain normothermia.

11. Remove the mattress.

12. Monitor rectal temperature for at least 24 hours after

achieving normothermia (36.5°C) (28).

Pitfalls

1. Intermittent manual adjustment of coolant fluid temperature is required.

2. Overshoot of core temperature during induction of

hypothermia.

3. Large swings in rectal temperature (29) (Fig. 45.11).

Cooling Using a Servocontrolled Cooling

Machine

The servocontrolled cooling systems cool and maintain the

core temperature by altering the temperature of the cooling

fluid automatically, based on the core and surface temperature feedback to the system. The infant can be placed inside

an incubator or preferably in an open bed.

1. The CritiCool (Fig. 45.12) (MTRE Advanced

Technologies Ltd, Yavne, Israel). Temperature

Management Unit

Other Equipment

a. Power cable

b. Connecting tubes

c. Cure wrap (MTRE Advanced Technologies Ltd,

Yavne, Israel)

334 Section IX ■ Miscellaneous Procedures

A B

D

E

C

F

Female end of connecting

tube to curewrap

< 3.5kg

Curewrap

Green surface temperature sensor

Connecting tubes to temperature

management unit

Water tank

Rectal temperature sensor tip

Cooling during

transport

Surface temperature sensor tip

Grey core (rectal) temperature sensor

> 3.5kg

 

336 Section IX ■ Miscellaneous Procedures

degree and duration can be individualized to

infant’s clinical condition in this mode.

(2) To select controlled rewarm mode, press menu,

select mode, press ▲ to move up or to move

down, and highlight the controlled rewarm

option. Press OK (Fig. 45.13C).

The message “CORE readout too low check

core and operate” will appear (Fig. 45.13D).

Core, skin, and target temperatures are

shown on the monitor of the temperature management unit (Fig. 45.13D). The water will no

longer be circulating in the wrap. The default

target temperature is 36.5°C; however, the set

target temperature can be varied between 36°C

and 38°C, using the ▲ or ▼ arrows below the

target temperature read out (Fig. 45.13D).

(a) To start controlled rewarming, press menu

and use the ▲ or ▼ arrows to select

Operation (Fig. 45.13E).

(b) Once Operation is highlighted, press the

Enter button to confirm (Fig. 45.13E).

(c) Once normothermia achieved, leave the

infant on the wrap for 12 hours.

(d) If the infant is in a crib in which the temperature of the mattress can be increased,

increase the temperature of the mattress to

1°C above the infant core temperature at

the end of the 12-hour period and remove

the wrap.

(e) Keep the infant’s head uncovered and

placed on the bubble wrap pillow to insulate the head from the heated mattress.

(f) Infant may be dressed in one layer of clothing.

(g) Monitor the rectal temperature for 24 hours

after achieving normothermia (approximately

36.5°C rectal) to avoid hypo- or hyperthermia.

Precautions

a. The CureWrap must be applied loosely (allow a

space of a finger width between the skin and the

wrap) around the trunk to avoid impeding ventilation and pressure on the skin from the monitoring

leads between the wrap and skin (Fig. 45.15).

b. Skin care must be performed a minimum of every

8 hours.

B

A

C

Fig. 45.14. Insulating the head with bubble wrap. A: Pillow is prepared with six layers of bubble wrap.

B: The layers of bubble wrap are rolled at one end to form a neck roll. C: CureWrap placed around the

doll; bubble wrap pillow is covered with sheet; the neck rests on the neck roll; aEEG electrode is fixed in

the parietal (P3) position.

Chapter 45 ■ Brain and Whole Body Cooling 337

c. An alarm will alert the user if the rectal or surface

probes become dislodged.

d. An alarm will sound if there is insufficient water in

the temperature management unit.

 

Fig. 45.12. A: CritiCool machine. B: Water tank to be filled with tap water to the area between the two

red lines. C: Tips of the rectal and skin temperature sensors. D: CureWrap with the Velcro fasteners for

infants 3.5 kg < and >3.5 kg. E: Connecting tube ends for insertion over the male connector of the

CureWrap.

Chapter 45 ■ Brain and Whole Body Cooling 335

d. Tap water

e. Rectal temperature probe ×2 (reusable) or adapter

with single-use rectal probes

f. Skin temperature probe (reusable) or adapter with

single-use probes

g. Layered bubble wrap pillow.

Technique

a. Position CritiCool unit and lock front wheels.

b. Fill tank of the temperature management unit with

tap water to between the two red lines (Fig. 45.12A, B).

c. Select the size of the CureWrap (“cooling jacket”)

appropriate to the size of the infant (<3.5 kg and

>3.5 kg) (Fig. 45.12D).

d. Connect the connecting tubes to the temperature

management unit and the CureWrap (Fig. 45.12A).

e. Pull the collar off the female end of the connecting

tube and insert over the male connector to the

CureWrap.

f. Connect the connecting tubes to the metallic sockets in front of the temperature management unit.

g. Switch on the temperature management unit after

connecting the power cable.

A prompt to confirm mode will appear with an

audio alarm.

h. Cure wrap will fill with water; ensure the CureWrap

is filled with water prior to wrapping and securing

on infant.

i. Confirm neonatal cooling mode (Fig. 45.13A).

The default set core temperature in the management unit is 33.5°C. Water will not flow in the wrap

without a valid core temperature reading.

j. Connect grey temperature sensor into Core socket

and green temperature sensor into Surface socket.

(Fig. 45.12A).

k. Circulation is confirmed when the “flow icon” (top

right of display) is rotating (Fig. 45.13B).

l. Place the infant in the supine position on the

CureWrap (which is shaped to fit the infant) in an

open crib/bed.

m. Undress the infant down to a small diaper.

n. Insert the rectal temperature probe (grey sensor)

supplied with the equipment 6 cm into the rectum

(see E) (Fig. 45.2A).

o. Insert a second calibrated rectal probe to 6 cm,

alongside the previous probe. The second probe is

connected to a separate patient monitor to serve as a

means to double check the rectal temperature.

p. Secure both the rectal temperature sensors (see E).

q. Cover the infant’s legs and the trunk with the

CureWrap, and secure with the Velcro straps (Fig.

45.14D).

r. Expose the umbilicus to allow insertion of umbilical

lines and monitoring for bleeding (Fig. 45.14D).

s. Place six layers of bubble wrap between the head

and the head portion of the wrap (Fig. 45.14B, C).

This insulates the head from the cycling temperature in the CureWrap (30). Keeping the head

exposed in an open bed maintains the superficial

brain colder (29). The experimental evidence indicates that the fluctuation in the mattress temperature every 12 minutes induces similar fluctuations

in the superficial brain temperature.

t. Secure the surface temperature probe to the forehead with tape (Fig. 45.14D).

u. Monitor core and surface temperature every 15 minutes during induction of HT and rewarming, and

every 30 minutes during maintenance phase of HT.

v. After 72 hours of HT, rewarm using either the manual or controlled mode.

(1) During the manual mode, the user increases the

set core temperature in the CritiCool by 0.2°C to

0.3°C per 30 minutes to increase the core temperature by 0.4°C to 0.5°C per hour. Rewarming

A, B

D E

C

Fig. 45.13. Setting up CritiCool for

neonatal cooling and automatic

rewarming mode. A–E show the LCD

display on the CritiCool.

 

f. Monitor core temperature (rectal or esophageal) for

72 hours duration of HT.

g. Apply blankets and change gloves and/or water

bottles as frequently as necessary to maintain core

temperature at 33.5 ± 0.5°C.

h. Rewarming can be achieved passively by discontinuing active cooling and monitoring the rise in core

temperature.

i. Gradual rewarming using external heat source, as

for passive cooling, can be used with appropriate

shield to protect the head (Figs. 45.6B, 45.21).

Fig. 45.8. Variability in the rectal temperature during initiation, maintenance, and rewarming phase of

HT. SHC, selective head cooling manual (CoolCap n = 21); WBCmc, whole body cooling manual control (Tecotherm n = 25); WBCsc, whole body cooling servocontrolled (CritiCool n = 28).

332 Section IX ■ Miscellaneous Procedures

Pitfalls

a. There should be minimal variation in ambient

temperature.

b. Some, but relatively less, variability in core temperature compared with passive cooling.

c. Frequent monitoring is required to determine when

the gloves/water bottles need replacing.

2 Gels (5) (Fig. 45.10)

Technique

a. Expose the infant to the ambient temperature in an

open crib with an overhead warmer turned off.

b. Apply two refrigerated gel packs (12 cm × 12 cm, at

7°C to 10°C) across the chest and/or under the head

and shoulders.

c. Remove one gel pack when the core temperature

falls below 35°C.

d. Remove the next gel pack when the core temperature falls below 34.5°C.

e. Turn on the radiant warmer and manually adjust the

heater output every 15 to 30 minutes if the core

temperature falls below 33.5°C and use appropriate

shield to protect the head (Fig. 45.21).

f. Reapply gel packs if core temperature rises above

34°C.

g. After 72 hours, increase the radiant warmer heater

output to achieve rewarming by 0.5°C every 1 hour.

Pitfalls

1. High variability of core temperature.

2. Intensive monitoring and support required to maintain

the desired core temperature.

3. Servocontrolled fan (27)

WBC is achieved using a custom-made, servocontrolled

fan, which directs airflow cephalocaudally over the

infant.

The fan unit consists of a Perspex box (30 × 15 × 10 cm)

containing three fans. The fans are noiseless and are placed

at the head of the infant. The unit produces an airflow of

105 ft/min at 100% power, and is powered on 12V direct

current via a custom-made power supply. The fans are activated when the rectal temperature is at or above the preset

activation temperature, and the power of the fans automatically increase or decrease with fluctuations in the rectal

temperature.

 

Technique

a. Place the infant in the supine position, with small

diaper on, in an open crib with overhead radiant

warmer turned off.

b. Insert a rectal temperature probe to 6 cm, as

described previously.

c. Connect the rectal temperature probe to the radiant

warmer temperature input.

Serial output from the radiant warmer provides

temperature data to the fan unit, via computer. The

software (Labview for Windows, National Instruments

Ltd, Austin, Texas) servo controls the power of the

fans within the fan unit.

d. Set the activation temperature of the fan manually,

well below the target core temperature (33.5°C),

and set the radiant warmer target temperature at

33.7°C. This allows the fan unit to consistently blow

at low power, while the warmer provides heat as

necessary to maintain the target rectal temperature.

e. After completing 72 hours of HT, rewarm by turning off the fan and progressively increasing the

target temperature on the radiant warmer to achieve

rewarming at a rate ≤0.5°C/h. Shield the head from

direct overhead heating (Fig. 45.21).

Fig. 45.10. Cooling with refrigerated gel packs placed under

the head and across the chest and trunk.

Fig. 45.9. Cooling with adjuncts. Gloves filled with cold water

are placed around the head, trunk, and legs to cool the infant, along

with rectal temperature monitoring.

Chapter 45 ■ Brain and Whole Body Cooling 333

Fig. 45.11. Infant cooled by a manually operated

Tecotherm TSmed 200N. Infant is inside a nonheated incubator. The temperature of the coolant in

the blanket is manually changed using the up and

down arrows beside the temperature display on the

cooling unit.

Pitfalls

Shivering can occur with higher fan speeds.

Cooling Using a Manual Control Cooling

Machine

Equipment

1. Tecotherm TSmed 200 N (TECCOM GmbH, Halle/

Salle, Germany) (Fig. 45.11)

2. Power cable

3. Cooling unit

4. Dual lumen connecting hoses

5. Cooling mattress (AquaPad mattress)

6. Coolant (Thermal fluid TECOmed)

7. Fill-up set

Technique (3)

1. Switch on the cooling unit after plugging in the power

cable.

 

Chapter 45 ■ Brain and Whole Body Cooling 331

likely in an infant at birth, passive cooling should be initiated as soon as ventilation is established (23). This method

of cooling can be effective for days, depending on the environmental temperature, but it is usually used only until

active cooling equipment is available (24).

Technique

1. No radiant warmer or other methods of warming should

be initiated.

2. Keep the infant uncovered (small diaper may remain in

place).

3. Monitor core temperature with rectal or esophageal

probe. If overcooling occurs, infant can be rewarmed

slowly with a heat source (e.g., warm water bottles, overhead heating [with heat shield to the head]) (Fig. 45.21).

4. Maintain ambient temperature below 26°C.

5. On completion of a 72-hour course of cooling, achieve

rewarming at a rate of 0.5°C/h (i.e., from 33.5°C to

36.5°C in 6 hours).

Pitfalls

1. Core temperature monitoring is required to avoid

excessive cooling (24,25).

2. Variability of core temperature during passive HT is

high (23,24).

Cooling with Adjuncts

1. Gloves/Bottles Filled with Tap Water (Fig. 45.9)

Technique

a. Expose the infant fully and place in an open crib.

b. Remove all heat sources.

c. Maintain ambient temperature between 25°C and

26°C.

d. Use three rubber water bottles, filled with cold tap

water, to form a mattress and/or

e. Place rubber gloves filled with water at approxima-tely 10°C next to the groins, axillae, and neck

(26).

 

330 Section IX ■ Miscellaneous Procedures

Precautions

1. Use only sterile water.

2. Monitor for scalp changes every 12 hours.

3. SHC may not be appropriate for babies weighing

<1.8 kg, due to reduced effectiveness of cooling in

small for gestational age infants (21).

4. Avoid having the straps on the blue Lycra cap too tight

to avoid swelling of the neck (Fig. 45.7).

Disadvantages

1. Involves repeated adjustments of the radiant warmer

output and Cool-Cap water temperature.

2. It is not possible to store temperature data.

3. Rewarming rate cannot be individualized to infant.

H. Whole Body Cooling (WBC)

WBC can be achieved by

1. Passive cooling.

2. Cooling with simple adjuncts such as water bottles, gloves

filled with water, gels, or fan.

These methods are effective, but they are more

difficult to use and are labor intensive. It is difficult to

achieve stable temperature over a long period.

3. Manually controlled cooling machine and mattress

4. Servocontrolled cooling machines with body wrap or

mattress.*

Temperature, blood pressure, and heart rate variation during cooling with manual and servocontrolled

WBC and manual SHC is shown in Figure 45.8.

Passive Cooling

After perinatal asphyxia, the metabolism of infants is naturally low, and the core temperature will fall unless active

warming is commenced (22). When perinatal asphyxia is

Neck swelling & impression caused

by tight water cap retainer strap

Fig. 45.7. Neck swelling and impression caused by placing the

strap of the water cap retainer too tightly.

A B

Fig. 45.6. A: Placement of insulating cap over the water cap retainer. The patches in the interior of the

insulating cap attach to the Velcro fasteners on the exterior of the water cap retainer. B: Heat shield placed

over the face and head of the infant.

*Each of these methods will be described with the corresponding figures.

 

i. Main hose support (Fig. 45.4)

j. Spiked fill tube (Fig. 45.3)

k. Cap tube support (optional) (Fig. 45.4)

l. Disposable module clips

m. Temperature sensor module (TSM) (Fig. 45.4)

n. Temperature probes: To monitor rectal, scalp, and

skin temperature, Tempheart shields (Fig. 45.4)

o. DuoDERM/Tegaderm or comparable dressing

p. Adhesive tape

q. Rectal lubricant

r. Optional sensors: Yellow Springs Instrument Co.

(YSI)-compatible temperature sensors, esophageal,

nasopharyngeal

Chapter 45 ■ Brain and Whole Body Cooling 327

Fig. 45.3. CoolCap (Olympic) system—

rear side showing control and cooling unit.

Fig. 45.4. Infant preparation for

CoolCap. Infant placed in a radiant

warmer bed with core, skin, radiant

warmer, and scalp temperature sensor connected to the infant and the

temperature sensor module.

328 Section IX ■ Miscellaneous Procedures

Technique

1. Place infant in open crib with appropriate cardiorespiratory support and diaper removed (Fig. 45.4).

2. Place the radiant warmer bed in a flat horizontal position (Fig. 45.4), with the warmer turned off.

3. Lock the caster brakes on the cooling unit.

4. Plug in the power cord, and press the power switch to

the on position.

5. Touch set up in the control unit (Fig. 45.3).

6. Enter Patient information for the setup wizard displays.

a. Required infant data: Weight and gestational age.

b. Optional data (can be entered during treatment):

Patient name, ID, date and time of birth, clinical

data and names of the optional sensors in use (see

Equipment, above).

c. Touch Next.

7. Connect Temperature sensors, for the setup wizard

displays.

a. Connect the TSM to the control unit aligning the

red dots, then attach the TSM to the infant’s bedding using the TSM clip (Figs. 45.3 and 45.4).

b. Connect the rectal temperature sensor to the module.

c. Secure rectal temperature sensor (see E).

d. Connect the scalp temperature sensor to the TSM

(Fig. 45.4).

e. Position the tip of the sensor lateral to the anterior

fontanel to allow cerebral ultrasound.

f. Apply DuoDERM/Tegaderm over the sensor.

g. Apply Tempheart shield (supplied with Cool-Cap

equipment), with the tip pointing toward the back of

infant’s head. Any generic sensor shield can be used.

h. Plug the skin temperature sensor into the TSM (Fig.

45.4).

i. Position the tip of the skin sensor over the liver on

the anterior abdominal wall.

 

j. Plug the radiant warmer temperature servo probe

into the radiant warmer.

k. Place the tip of the radiant warmer servo probe by

the side of the skin probe.

l. Apply Tempheart shields over the skin and radiant

warmer servo probes.

m. Connect optional temperature sensors, such as esophageal, nasopharyngeal, or tympanic sensors, to the TSM.

n. After confirming that each task is complete, touch next.

8. Enter Cap temperature, for the setup wizard displays

(see Table 45.1).

a. Cap temperature might have to be set higher,

depending on infant’s general condition (e.g.,

administration of drugs such as anticonvulsants, cardiac impairment requiring inotropes) to avoid overshooting of core temperature.

b. Touch ▲ to increase or ▼ to decrease the water

temperature. Each touch will increase or decrease

the desired cap water temperature by 0.1°C.

c. When the desired cap water temperature displays,

touch next.

9. Make the water connections, for the setup wizard displays.

a. Installing main hose support (Figs. 45.3 and 45.4)

(1) Place the main hose support on the wall of the

warmer bed, with the black inner foam contacting the wall.

(2) Rotate the knob clockwise to tighten the support.

(3) Position the main hose support so that there

is an easy access to the back of the cooling

unit.

b. Placing Cap tube support (Fig. 45.4): Slide the cap

tube support as far under the mattress as possible.

c. Filling the cooling unit with sterile water (Fig. 45.3)

(1) Spike a new 1-L sterile water bag with fill tube.

(2) Hang the bag on the back of the cooling unit.

(3) Connect the spiked fill tube to the FILL connector.

(4) Clear any kinks in the tube.

d. Making main hose connections (Figs. 45.3 and 45.4)

(1) Slide the dovetail of the main hose into the

dovetail slot on the back of the cooling unit.

(2) Connect the main hose to the cooling unit—red

to In, blue to Out.

(3) Slide the dovetail of the distal end of the main

hose into the dovetail slot of the main hose

support.

e. Making Cap connections

(1) Select the appropriate cap size based on weight

and head circumference (Table 45.2).

(2) Slide the cap connector tubes fully onto the

water cap flanges; red to red, blue to blue (Fig.

45.5A).